Pump loading and unloading mechanism



June 21, 1927. 1,633,035

P. W. RECK PUMP LOADING AND UNLOADING MECHANISM Filed Dec. 11, 1926 2Sheets-Sheet l Fig-1 I Peck HZZDT'ITZEFS,

June 21 1927.

P. w. RECK PUMP LOADING AND UNLOADING MECHANISM Filed Dec. 11, 1926 2Sheets-Sheet 2 InUEnZar'.

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Patented June 21, 1927.

UNITED STATES PATENT OFFICE.

PETER W. RECK, O1 IBETTENDORF, IOWA, ASSIGNOR TO THE BETTENDORR COMPANY,

OF BETTENDORF, IOTA, A CORPORATION OF IOWA.

PUMP LOADING AND UNLOADIN G MECHANISM.

Application filed December 11, 1926. Serial No. 154,128.

This invention relates to pumps and particularly to control devices forloading and unloading pumps for high pressure service.

It has heretofore been common practice to continuously operatereciprocating pressure again load the pump. The present inventioncontemplates an improved control mechanism for governing the operationof the intake or suction valvesof pumps of the above character.

Valve control mechanism has heretofore been proposed for loading andunloading pumps of the above character in such manner as to graduallyincrease or gradually reduce the torque imposed on the crank shaft ofthe pump by lifting or releasing the suction valves of the pump inprearranged sequence at a particular stage in the pumping cycle of eachcylinder. Certain of the previously proposed mechanism positively holdsthe intake valves of the ump in their open position after they are iftedby the intake suction of the pumps. The operation of these systems isuncertain because the intake suction of the pump is required to lift theintake valves to substantially their full open position before the valveholding mechanism operates. It will be apparent that, if the lift of theintake valve is less than its full open stroke, or if the valve sticks,the pump will continue to develop pressure. The dangers incident to suchuncertainty of operation of hydraulic pumps handling ressures, which attimes exceed several tiousand pounds er square inch, will be apparent tothose s illed in the art.

Valve control mechanism has also been proposed heretofore in which theintake valves are opened by the application of -yielding spring pressurethat acts through a rocker arm againstthe push rod of the'valve and theinternal pressure in the pump cylinder. The intake valves of thesesystems are yieldingly held in their open position when the pump isunloaded and they often close against the yielding force of the valveactuator during the pressure stroke of the pump with consequent severewater hammer which imposes enormous strains on the pumping equipment anddefeats the purpose of regulated sequence control. For the abovereasons, neither of the previously proposed methods of control of theintake valves of systems of the character herein described have beencommercially practical.

The present invention proposes mechanism for yieldingly opening theintake valves of the pump, in order that the valves will be opened onlyduring the intake stage of the pumping cycle, and also providesmechanism for positively holding the valve in its open position afteractuation. The proposed mechanism can be used without or in connectionwith a sequence control system for selpctively loading the several pumpcyl- 1n ers.

The primary object of the invention is to provide a system of controlfor reciprocating pumps of the above character that yieldingly opens theintake valves of the pump during the intake stage only andthatpositively locks the valve in its after actuation.

Another object of the invention is to provide reliable positivelyactuated means for open position i loading or unloading the pump that iscommerciall practicable and that is adapted to gradually apply or reducethe operating torque imposed on the crank shaft of the pump in loadingand unloading operations.

Another object of the invention is to provide improved cam actuatedmechanism for positively actuating the intake valve as quickly as thepressure within the pumping cylinder is reduced td a value that can beovercome by the regulated pull of a control spring or other yieldingvalve actuator.

Other objects and advantages to be derived from practicing the inventionwill be apparent to those skilled in the art from consideration of theaccompanying description of a referred embodiment of the invention asillustrated in the accompanying drawings wherein:

Figure 1 is a sectional elevational view, taken on line 1-1 of Fig. 2,of a portion of v the cylinder block and intake valve mechanism of anaccumulator pump constructed in accordance with this invention. I

F 1g. 2 IS an enlarged side elevational View of the control mechanismfor one of the cylinders of the pump shown in Fig. 1.

Fig. 3 is an enlarged detail sectional 'view taken substantially on line3--3 of Fig. 1 looking in the direction of the arrows and showing thecam mechanism for actuating the inlet valve. The cam -mechanism is shownin this view in the loaded position of the pump; and

Fig. 4 is a similar View of the sectional cam mechanism shown in theposition in which the pump is unloaded, indicating in dotted outline theintermediate transition position of the cam.

For the purpose of illustrating the invention, it is shown as embodiedin a conventional form of Blake horizontal duplex double actingreciprocating pressure pump intended for use in developing relativelyhigh hydraulic pressures.

The illustrated portion of the pump comprises 'a cylinder block 1 thathas a pressure developing" reciprocating piston 2 operating within acylinder or pressure chamber 3 of ,the pump. A conventional form ofconnecting rod 4 serves to operate the piston. Liquid is admitted to thepump through inlet valves 5, each of which has a valve seat 6, a guide 7and a push rod 8 associated therewith. There may be one or moreof thesevalves for each cylinder of the pump, depending upon the character ofpump to which the invention is applied. The remainder of the pumpstructure is of conventional design, embodying any desired number ofduplicate pump elements, as will be understood by those skilled in theart. The remainder of the pump structure is not illustrated hereinbecause it would serve only to complicate the description of the presentinvention. I

The loading and unloadingof each cylinder orv pressure chamber of thepump is controlled from one or more duplicate valve actuatingmechanisms, of which the cam mechanisms 9 and 10 that are governed by asolenoid 11 and a control spring 12 that is associated therewith, arerepresentative. This cam mechanism and the associated control forgoverning the intake valves of the pump constitutes the particularsubject matter,of the present invention. The solenoids of the system arepreferably althou%h not necessarily energized. in prearrange sequence bany suitable control mechanism (not shown as will be apparent to thoseskilled in the art.

Each solenoid, when energized, serves to lift the crank pins 19 of apair of bell cranks 13, to which connecting rods 14 of the solenoidextend, against the compressive force of the control spring 12. Thecontrol spring 12 normally serves to maintain the pump cylinder in itsunloaded condition when the associated solenoid is deenergized. Eachbell crank is carried at one end of a cam shaft 15 that has a cam 16secured to the other end thereof. The. cam 16 engages the cooperatingface of a second pivotally,

out substantial development of pressures in the pumping chamber.

The contacting surfaces of the cams 16 and 17 are so related as tofacilitate actuation of the cam arm 17 by the operating cam 16 tosubstantially a dead center position with respect to the opposing thruston the push rod 8. The are of movement of the crank arm is relativelysmall so that it is always in position to effectively control movementof the cam 16 to its extreme oper ative positions. In order to moreclearly illustrate this relation of the cams 16 and 17, a dash and dotline 17 a is drawn between the contact centers of the cam arm 17 and acorresponding line 16 is drawn through the center of the contactingsurfaces of cams 16 and 17 normal to the line 17 The relation of theselines show a desired substantially dead center position of the cams withrespectto the push rod 8 and also show a preferred angularity of thecontacting surfaces that facilitates actuation of the cams in eachdirection of movement.

The dotted outline 16 and 17 of the respective cams 16 and 17illustrates the transition position of the cams when the internalpressure of the pump chamber prevents ac-' tuation of the push rod 8.The transition position of the cams is such that yielding liftingpressure is applied to the push rod 8.

The actuation of the valve does not take place, however, until thepressure in the pump cylinder is less than the force thus applied whichprevents actuation of thevalve when the cylinder is loaded. Afteractuation of the valve, however, an enormous force on the push rod 8would be required to move the cams a ainst the force of the controlspring 12. is insures positive locking of the valve in its open positionby mechanism adapted to apply yielding lifting force thereto.

The range of movement of the crank arm 13 is diagrammaticallyillustrated in'Fig. 3

and Fig. 4 by the change in position of the of the mechanisms 9 and 10are mounted in a support 21 that has a flanged base 22 that is securedto the pump frame 23 by suitable nuts 24. A stuifing box 25 preventsleakage from the liquid supply along the cam shaft 15.

' The cam 17 is maintained on its pivot pm 27 by a suitable bracket 28that is carried on an extension 29 of the support 21. The extension 29also provides a guide for the lower end of the push rod 8.

If it is assumed that the pump is operating' to develop pressure, thatis with the valve control mechanism in the position shown in Fig. 1,Fig. 2 and Fig. 3, and it IS desired to unload the pump because theaccumulator pressure has reached a predetermined operating value or forany other reason, the solenoid 11 is deenergized which causes theoperating spring 12 to rotate the chamber of the pump cams 16 and 17 tothe transition positions 16 and 1?". In this position of the cams apredetermined operating force is yieldingly applied to the push rod 8 ina direction tend U5 mg to open the associated valves 5 against theinternal pressure of the cylinder 3. This yielding pressure from thespring 12 is transmitted through the crank arm 13 and crank shaft 15 tothe cam 16 which it tends to rotate-in the direction of the arrow 30that is shown associated therewith in Fig. 3 of the drawings. The camarm 17, which the cam 16 tends to lift, engages the adjacent end of thevalve push rod 8. If the internal pressure of the pressure chamber 3exceeds t e yieldingly applied pressure from-the spri. g 12 on the pushrod 8, then the cams rema n in the transition stage indicated in thedotted outline positions 16 and 17 of Fig. l and the valves remainseated until the conclusion of the pressure stroke.

After the completion of the pressure stage of the pumping cycle, thepressure within the pumping chamber 3 is reduced to a value less thanthe yielding pressure imposed on the push rods 8. This permits the earns17 to pass through the transition positions 16* v and 17 and to lift theassociated valves 5 against the internal pressure of the pump cylinderto thereb unload the pump. Any desired number OI intake valves for apressure chamber can be controlled from a single solenoid or othersuitable actuating mechanism.

If a single control mechanism is used for deener 'zing all of theactuating solenoids 11 of t e pump mechanism, or if an equivalentmechanical control unit is used to simultaneously release or release insequence the upward ull on crank arms 14 that act against t e spring 12,then the load on the pumping system is released simultaneously or insequence except as to those pressure chambers of the pump that are 0crating in the pressure developing stage of their pumpparticularcylinders that by the 'as applicant is aware. Applicants art that thisrelease of the load on the pump will be much faster than a release thatis dc pendent upon the lifting of the valves 5 by thesuction stroke of.the pump before the valves are'locked in their open positions. Everycylinder is unloaded except those are in the pressure developing stageof their cycle. Formerly the respective cylinders were not unloadeduntil the cycle of operation of each cylinder passed well into theintake stage of the pumping operation and the release at this stage wasdependent upon substantially the full movement of the intake valve bythe suction of the pump, making the release of the load uncertain.

- It will also beapparent to those skilled in the art that the liftingof the intake valves yielding force of the springs 12 provides acertainty of operation of the valve control mechanism that cannototherwise be obtained and that the positive locking of the valve in itslifted position by so relating the cam faces as to positively lock thevalve in its open position against all pressures to which the valve canbe subjected, recludes premature closure of the intake va ve when it isheld in its open position.

In again loading the pump, the solenoids 11 are successively energizedat the termination of the pressure stroke or during the intake stroke bysuitable control mechanism, or an equivalent mechanical device serves tosuccessively actuate the connecting. rods 14. against the compressiveforce of the springs 12 to successively rotatethe crank arms to thepositions shown in Figs. 1, 2'and 3, thereby permitting the intakevalves 5 to seal only at the termination of their intake strokes. Theload on the pump is thereby gradually applied because the intake valves5 will take a position corresponding to the position of each cylinder inthe pumping cycle. The advantages of providing cam actuated mechanismthat is suitable for commercial use in pump structures of the typesherein proposed will be apparent to those skilled in the art;

This is the only form of satisfactorily operating valve'controlmechanism that is com mercially in use at the present time so farproposed cam acting valve lift is so designed and arranged as to givereliable operation of the valve at all times. The mechanism permits aneffective seal to be formed between the operating solenoid and the valvelift mechanism that is mounted within the supply chamber of the pump..The specific form of cam members are also arranged to cooperate "withvery little frictional resistance. It also will be obvious that therelease of the pump load is much quicker in applicants device than inapparatus heretofore proposed with all of the advantages of distributedreduction in the torque load imposed on the crank shaft of the pump.

pressure stage of the pumping cycle whereby said valve is actuated bysaid mechanism only when the actuating force applied to the push rod isless than the opposing force of the internal pressure of the pressurechamher acting on said valve, said mechanism' comprising a bell crankactuated by said pressure means, a cam shaft on which the bell crank'ismounted, a stufling box throu h which the shaft extends, a cam carried ythe cam shaft remote from the bell crank, and a second pivotally mountedcam actuated by the first cam to impose lifting force on. the push rodwhen the cam shaft is actuated.

2. The combination with a pump having a pumping chamber, a suctionvalve, and a push rod for lifting said I valve from its seat, ofmechanism for loading and unloading the pump comprising a pivotallymount ed cam arm adapted to act against said push rod to lift the valve,a second cam adapted to actuate the first cam, a shaft for the secondcam, a stufling box for the shaft, a bell crank on one end of the shaft,and means for yieldingly operating the bell crank to lift the suctionvalve of the pump.

3. The combination with a pump having a pumping chamber, a suctionvalve, and a push rod for lifting said valve from its seat, of mechanismfor loading and unloading the pump comprising a pivotally mounted camarm adapted to act against said push rod to lift the valve, a second camadapted to actuate the first cam, a shaft for the second cam, and meansfor yieldingly operating the first cam to lift the suction valve of thepump.

4. The combination with a pump havin a pumping chamber, a suction valve,an a push rod for lifting said valve from its seat, of mechanism forloading and unloading the hydraulic pump having pump comprising apivotally mounted cam arm adapted to act against said push rod to liftthe valve, a second cam adapted to actuate the first cam, a shaft forthe second cam, and means for yieldingly operatin the first cam to liftthe suction valve 0? the pump, said second cam being adapted to move tosubstantially a dead center position with respect to the force on thepush rod when the valve is held in its full open position.

5. The combination with a reciprocating hydraulic pump having a pressurechamber, a liquid supply chamber, a suction valve between the chambers,and a push rod for lilting said valve from its seat, of pump loading andunloading mechanism comprising a solenoid, a bell crank actuated by thesolenoid, means yieldingly opposing the actuation of the bell crank bythe solenoid, a cam actuated by the bell crank, a second pivotallymounted cam arm actuated by the first cam and adapted to exert yieldingvalve lifting pressure upon-said push rod.

6. The combination with a reciprocating hydraulic pump having a pressurechamber, a liquid supply chamber, a suction valve between the chambers,and a push rod for lifting said valve from its seat, of pump loading andunloading mechanism comprising means for imposing yielding valve liftingforce on the push rod adaptedto substantially lock the valve in itsraised position after actuation by said yielding force, and meansrendering said first means inoperative.

.7. The combination with a reciprocating hydraulic pump having apressure chamber, a liquid supply chamber,,and a suction valve betweenthe chambers, of. pump loading and unloading mechanism comprising meansfor yieldingly lifting the valve by application of a force of materiallylesser magnitude than the force applied to said valve during thepressure stroke-of the pump and for substantially locking said valve inits raised position after its yielding actuation, and control means forrendering said valve lifting means inoperative.

38. The combination with a reciprocating a pressure chamber, a liquidsupply chamber, and a suction valve between the chambers, of pumploading and unloading mechanism comprising a. cam shaft having a bellcrank on one end and a cam on the other end thereof, a connecting rodfor actuating the bell crank, a control spring acting to rotate said camshaft, and means under the control of the operator for rendering saidcontrol spring inoperative'to rotate said cam shaft.

9. The combination with a reciprocating hydraulic pump having a pressurechamber, a liquid supply chamber, and a suction valve between thechambers, of pump loading and unloading mechanism comprising a pivot-Ill ally mounted arm adapted to apply lifting force to said valve, a camacting on the arm to actuate the same into lifting engagement with thevalve and for yieldingly holding I the cam in actuating relation inrespect to the valve, and means for rendering said mechanisminoperative.

10. The combination with a reciprocating hydraulic pump having apressure chamber, 10 a liquid supply chamber, and a suction valvebetween the chambers, of pumploading and unloading mechanism comprisinga push rod for controlling said intake valve, a rocker arm acting on thepush rod to lift the valve from its seat, a cam acting on the rockerarm, means normally tending to rotate said cam in a direction tending tolift said valve from its seat, and means for rendering said liftingmeans inoperative. Y

In testimony whereof I aflix my signature.

PETER W. RECK.

